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Selective attention Bees playing video games show they actively choose what they want to pay attention to in a similar way to humans, rather than simply reacting to external stimuli.

Researchers from the Queensland Brain Institute conducted a novel experiment which involved implanting electrodes into the brains of bees, then tethering them so they couldn't fly and placing them on an air-suspended ball that they could steer by walking to control the movement of a blinking light on a screen.

The research examines whether bees are capable of choosing to focus their attention — something called 'top-down attention' — or whether they are only capable of reacting to something external like a bright light or noise, called bottom-up attention.

"A lot of animals have is this bottom-up attention but often when we think of attention as humans, we think of it as almost related to consciousness, this goal-directed attention," says lead researcher Associate Professor Bruno van Swinderen.

"Instead of being reactive, you're choosing something and that choice exists in your brain before you make any kind of motor behaviour ... so we're interested in finding ways to see if an insect has that."

Virtual reality

The research team faced a number of challenges in exploring this question, the main one of which was how to work out what a bee is paying attention to.

In the past, this question has been explored with bees in flight, but this time researchers needed to record directly from the bees' brains during the course of the experiment, which cannot be done while the bee is flying.

Instead the bee was tethered to an air-suspended ball so the insect could control the movement of the ball by walking in different directions (see video below).

"The next hurdle was to have the bee control a virtual object, like in a video game, as it's walking." van Swinderen says.

"If we do something called closed loop biofeedback, where the turning of the ball controls the position of a virtual object on a screen surrounding the bee, then the bee can in effect control the position of the object by its behaviour."

The virtual objects in question were green lights, each of which was flashing at a different frequency. This enabled the researchers to tell exactly which light the bee was looking at because the electrodes in the bee's brain would pick up a corresponding frequency of brain activity depending on the frequency of the light flash — a technique often used in attention studies in humans.

Top-down attention

With this complex arrangement, the team made a number of interesting discoveries, the first of which was that bees are capable of top-down attention.

"There was a level of prediction that happens in the brain — which is the top-down part — so when we see a frequency tag that's associated with an object suddenly starts flaring up in the optic lobes, it means the bee will actually select that object and move it to the front and walk towards it," says van Swinderen .

Another discovery is that the bee's attention mechanisms are actually located in the parts of the brain that process visual information, rather than in the central brain, which is associated with learning and memory and higher cognitive functions.

"These decisions are being made quite early on, a couple of synapses from the photoreceptors," says van Swinderen.

This pushing of attention-based activities out into the sensory periphery in animals with tiny brains such as bees may be important for effectively navigating complex visual environments, the researchers suggest.

Van Swinderen says the experiments shed more light on the intelligence of these tiny creatures.

"People always knew that bees were smart — they've got their dance language and do all these really sophisticated kinds of learning — it's just that we haven't had methods for knowing what's happening in their brain when they're doing these smart things," he says.

"The surprise now is that what's happening in their brain when they're doing these smart things is quite similar to what's happening in the human brain."